I have a Performance Box its a great tool for comparison.
However I remember being tested on Datron & I assume that was correct & the PB was not that accurate. Remember 0-100 6.8 on PB came back as 7.1 on the Datron that's a 4.4% error. Since then ive not believed the box its good for its price but that 4.4% error would be 8.8mph at 200mph.